THAIPOTAMON CHULABHORN N.SP., A NEW FRESHWATER CRAB FROM (DECAPODA, BRACHYURA, POTAMIDAE)

BY

PHAIBUL NAIYANETR Department of , Faculty of , University, , Thailand ABSTRACT A new species of freshwater crab, Thaipotamonchulabhorn, is described from Thailand. The species is closest to Thaipotamondansai Ng & Naiyanetr, 1993; the differences between the two are discussed. A few notes on the biology and ecology of the new species are provided.

ZUSAMMENFASSUNG Eine neue Art Süsswasserkrabbe aus Thailand, Thaipotamonchulabhorn, wird beschrieben. Sie steht Thaipotamondansai Ng & Naiyanetr, 1993, am nächsten. Die Unterschiede zwischen beiden sind angegeben worden, sowie einige Bemerkungen über Biologie und Oekologie der neuen Art.

INTRODUCTION

In October 1991, Mr. Prasasna Ruttanaphuya, Editor of Thirabsung News- paper, Maha Sarakham Province, N.E. Thailand, collected 7 specimens of a new species of freshwater crab of the genus Thaipotamon Ng & Naiyanetr, 1993, belonging to the family Potamidae Ortmann, 1896. The specimens were found in the swamp Bung Dun Lumphun in Amphoe Na Chuak (= Na Chuak district), Maha Sarakham Province, north-eastern part of Thailand. Six living specimens of the same species were collected from the same place in November 1991. The description of the new species is provided in this paper. The holotype and a pair of paratypes of the new species are deposited in the collection of National Museum of Natural History (RMNH), Leiden, The and paratypes are deposited in the collection of Chulalongkorn University, Museum of Zoology, Bangkok, Thailand (CUMZ) and in Natur- Museum Senckenberg, Frankfurt am Main, Germany (SMF). The abbreviations cl. and cb. are used for carapace length and carapace width, respectively.

Thaipotamon chulabhorn new species (fig. 1, pl. 1) - Materials. Bung Dun Lumphun Swamp, Amphoe Na Chuak, Maha Sarakham Province, N.E. Thailand, in a burrow in the swamp, 25 October 1991, leg. P. Ruttanaphuya, 1 holotype (RMNH, Crust. D no. 41613), 1 0', 1 9 paratype; same locality, 12 November 1991, leg. P. Naiyanetr, 2 0', 2 9 paratypes. 2

- Measurements. Holotype 1 (Y, cl. 31 mm, cb. 40 mm; paratypes: 5 0", cl. 24-31.5 mm, cb. 33-40.5 mm, 5 9, cl. 23-32.5 mm, cb. 30-42.5 mm. - Etymology. The specific name is given in honour of Her Royal Highness Princess Chulabhorn, at the occasion of Her Royal Highness's 36th birthday, as a token of respect, and in recognition of Her Highness's important contribu- tions to the promotion of education, science and public health in Thailand, as well as Her efforts to bring an acceptable balance between industrial develop-

Fig. 1. Thaipotamonchulabhorn n.sp. a, carapace in frontal view; b, anterior part of carapace in dorsal view; c, cr abdomen; d, 0' first gonopods; e, o' second gonopod.